The present invention pertains generally to the tailstock of a machine lathe and the providing of an attachment therefor for the precise, powered advancement of the tailstock quill during a machining operation.
Typically lathe tailstocks are provided with a handwheel and a lead screw rotated thereby. A tool carrying quill in threaded engagement with the lead screw advances or retracts relative the end of a workpiece chucked in the lathe headstock. The rate of feed of the tool toward the workpiece is conventionally controlled by the degree of operator exerted force on the tailstock handwheel. Where repeated or extensive boring operations are performed, considerable physical effort of the operator is required. Further, the operator is required to give his full attention to the entire duration of the machining operation at hand.
The prior art includes mechanisms for the powering of tailstocks as, for example, a hydraulic device wherein a quill is actuated by a hydraulic cylinder provided by metering valves per U.S. Pat. No. 4,048,881. A motor driven lead screw and quill arrangement are shown in U.S. Pat. No. 3,198,042 and function to automatically compensate for thermal expansion or contraction of large lathe mounted workpieces such as metal rolls from which steel plate is rolled. U.S. Pat. No. 2,247,562 discloses an electric motor in direct drive with a lead screw to automatically maintain desired thrust against a workpiece end. Italian Pat. No. 489,554 shows a tailstock adapted for rotation by a lathe drive screw. U.S. Pat. No. 1,326,597 discloses a tailstock center 20 which may be biased into workpiece engagement by a powered shaft in geared connection with the tailstock. A manual clutch includes a handwheel and a nut element for urging the handwheel into engagement with a spur gear rotatably carried on a tailstock lead screw extension.